Merge branch 'refs/heads/t/command_handler_cleanups'
[paraslash.git] / command.c
1 /*
2 * Copyright (C) 1997 Andre Noll <maan@tuebingen.mpg.de>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file command.c Client authentication and server commands. */
8
9 #include <netinet/in.h>
10 #include <sys/socket.h>
11 #include <regex.h>
12 #include <signal.h>
13 #include <sys/types.h>
14 #include <osl.h>
15 #include <arpa/inet.h>
16 #include <sys/un.h>
17 #include <netdb.h>
18
19 #include "para.h"
20 #include "error.h"
21 #include "crypt.h"
22 #include "sideband.h"
23 #include "command.h"
24 #include "server.cmdline.h"
25 #include "string.h"
26 #include "afh.h"
27 #include "afs.h"
28 #include "server.h"
29 #include "list.h"
30 #include "send.h"
31 #include "sched.h"
32 #include "vss.h"
33 #include "net.h"
34 #include "daemon.h"
35 #include "fd.h"
36 #include "ipc.h"
37 #include "user_list.h"
38 #include "server.command_list.h"
39 #include "afs.command_list.h"
40 #include "signal.h"
41 #include "version.h"
42
43 typedef int server_command_handler_t(struct command_context *);
44 static server_command_handler_t SERVER_COMMAND_HANDLERS;
45 server_command_handler_t AFS_COMMAND_HANDLERS;
46
47 /* Defines one command of para_server. */
48 struct server_command {
49 /* The name of the command. */
50 const char *name;
51 /* Pointer to the function that handles the command. */
52 server_command_handler_t *handler;
53 /* The privileges a user must have to execute this command. */
54 unsigned int perms;
55 /* One-line description of the command. */
56 const char *description;
57 /* Summary of the command line options. */
58 const char *usage;
59 /* The long help text. */
60 const char *help;
61 };
62
63 static struct server_command afs_cmds[] = {DEFINE_AFS_CMD_ARRAY};
64 static struct server_command server_cmds[] = {DEFINE_SERVER_CMD_ARRAY};
65
66 /** Commands including options must be shorter than this. */
67 #define MAX_COMMAND_LEN 32768
68
69 extern int mmd_mutex;
70 extern struct misc_meta_data *mmd;
71 extern struct sender senders[];
72 int send_afs_status(struct command_context *cc, int parser_friendly);
73
74 static void dummy(__a_unused int s)
75 {
76 }
77
78 static void mmd_dup(struct misc_meta_data *new_mmd)
79 {
80 mutex_lock(mmd_mutex);
81 *new_mmd = *mmd;
82 mutex_unlock(mmd_mutex);
83 }
84
85 /*
86 * Compute human readable string containing vss status for given integer value.
87 *
88 * We don't want to use vss_playing() and friends here because we take a
89 * snapshot of the mmd struct and use the copy for computing the state of the
90 * vss. If the real data were used, we would take the mmd lock for a rather
91 * long time or risk to get an inconsistent view.
92 */
93 static char *vss_status_tohuman(unsigned int flags)
94 {
95 if (flags & VSS_PLAYING)
96 return para_strdup("playing");
97 if (flags & VSS_NEXT)
98 return para_strdup("stopped");
99 return para_strdup("paused");
100 }
101
102 /*
103 * return human readable permission string. Never returns NULL.
104 */
105 static char *cmd_perms_itohuman(unsigned int perms)
106 {
107 char *msg = para_malloc(5 * sizeof(char));
108
109 msg[0] = perms & AFS_READ? 'a' : '-';
110 msg[1] = perms & AFS_WRITE? 'A' : '-';
111 msg[2] = perms & VSS_READ? 'v' : '-';
112 msg[3] = perms & VSS_WRITE? 'V' : '-';
113 msg[4] = '\0';
114 return msg;
115 }
116
117 /*
118 * Never returns NULL.
119 */
120 static char *vss_get_status_flags(unsigned int flags)
121 {
122 char *msg = para_malloc(5 * sizeof(char));
123
124 msg[0] = (flags & VSS_PLAYING)? 'P' : '_';
125 msg[1] = (flags & VSS_NOMORE)? 'O' : '_';
126 msg[2] = (flags & VSS_NEXT)? 'N' : '_';
127 msg[3] = (flags & VSS_REPOS)? 'R' : '_';
128 msg[4] = '\0';
129 return msg;
130 }
131
132 static unsigned get_status(struct misc_meta_data *nmmd, int parser_friendly,
133 char **result)
134 {
135 char *status, *flags; /* vss status info */
136 /* nobody updates our version of "now" */
137 long offset = (nmmd->offset + 500) / 1000;
138 struct timeval current_time;
139 struct para_buffer b = {.flags = parser_friendly? PBF_SIZE_PREFIX : 0};
140
141 /* report real status */
142 status = vss_status_tohuman(nmmd->vss_status_flags);
143 flags = vss_get_status_flags(nmmd->vss_status_flags);
144 clock_get_realtime(&current_time);
145 /*
146 * The calls to WRITE_STATUS_ITEM() below never fail because
147 * b->max_size is zero (unlimited), see para_printf(). However, clang
148 * is not smart enough to prove this and complains nevertheless.
149 * Casting the return value to void silences clang.
150 */
151 (void)WRITE_STATUS_ITEM(&b, SI_STATUS, "%s\n", status);
152 (void)WRITE_STATUS_ITEM(&b, SI_STATUS_FLAGS, "%s\n", flags);
153 (void)WRITE_STATUS_ITEM(&b, SI_OFFSET, "%li\n", offset);
154 (void)WRITE_STATUS_ITEM(&b, SI_AFS_MODE, "%s\n", mmd->afs_mode_string);
155 (void)WRITE_STATUS_ITEM(&b, SI_STREAM_START, "%lu.%lu\n",
156 (long unsigned)nmmd->stream_start.tv_sec,
157 (long unsigned)nmmd->stream_start.tv_usec);
158 (void)WRITE_STATUS_ITEM(&b, SI_CURRENT_TIME, "%lu.%lu\n",
159 (long unsigned)current_time.tv_sec,
160 (long unsigned)current_time.tv_usec);
161 free(flags);
162 free(status);
163 *result = b.buf;
164 return b.offset;
165 }
166
167 static int check_sender_args(int argc, char * const * argv, struct sender_command_data *scd)
168 {
169 int i;
170 /* this has to match sender.h */
171 const char *subcmds[] = {"add", "delete", "allow", "deny", "on", "off", NULL};
172
173 scd->sender_num = -1;
174 if (argc < 3)
175 return -E_COMMAND_SYNTAX;
176 for (i = 0; senders[i].name; i++)
177 if (!strcmp(senders[i].name, argv[1]))
178 break;
179 PARA_DEBUG_LOG("%d:%s\n", argc, argv[1]);
180 if (!senders[i].name)
181 return -E_COMMAND_SYNTAX;
182 scd->sender_num = i;
183 for (i = 0; subcmds[i]; i++)
184 if (!strcmp(subcmds[i], argv[2]))
185 break;
186 if (!subcmds[i])
187 return -E_COMMAND_SYNTAX;
188 scd->cmd_num = i;
189 if (!senders[scd->sender_num].client_cmds[scd->cmd_num])
190 return -E_SENDER_CMD;
191 switch (scd->cmd_num) {
192 case SENDER_ON:
193 case SENDER_OFF:
194 if (argc != 3)
195 return -E_COMMAND_SYNTAX;
196 break;
197 case SENDER_DENY:
198 case SENDER_ALLOW:
199 if (argc != 4 || parse_cidr(argv[3], scd->host,
200 sizeof(scd->host), &scd->netmask) == NULL)
201 return -E_COMMAND_SYNTAX;
202 break;
203 case SENDER_ADD:
204 case SENDER_DELETE:
205 if (argc != 4)
206 return -E_COMMAND_SYNTAX;
207 return parse_fec_url(argv[3], scd);
208 default:
209 return -E_COMMAND_SYNTAX;
210 }
211 return 1;
212 }
213
214 /**
215 * Send a sideband packet through a blocking file descriptor.
216 *
217 * \param scc fd and crypto keys.
218 * \param buf The buffer to send.
219 * \param numbytes The size of \a buf.
220 * \param band The sideband designator of this packet.
221 * \param dont_free If true, never deallocate \a buf.
222 *
223 * The nonblock flag must be disabled for the file descriptor given by \a scc.
224 *
225 * Stream cipher encryption is automatically activated if necessary via the
226 * sideband transformation, depending on the value of \a band.
227 *
228 * \return Standard.
229 *
230 * \sa \ref send_sb_va().
231 */
232 int send_sb(struct stream_cipher_context *scc, void *buf, size_t numbytes,
233 int band, bool dont_free)
234 {
235 int ret;
236 struct sb_context *sbc;
237 struct iovec iov[2];
238 sb_transformation trafo = band < SBD_PROCEED? NULL : sc_trafo;
239 struct sb_buffer sbb = SBB_INIT(band, buf, numbytes);
240
241 sbc = sb_new_send(&sbb, dont_free, trafo, scc->send);
242 do {
243 ret = sb_get_send_buffers(sbc, iov);
244 ret = xwritev(scc->fd, iov, ret);
245 if (ret < 0)
246 goto fail;
247 } while (sb_sent(sbc, ret) == false);
248 return 1;
249 fail:
250 sb_free(sbc);
251 return ret;
252 }
253
254 /**
255 * Create a variable sized buffer and send it as a sideband packet.
256 *
257 * \param scc Passed to \ref send_sb.
258 * \param band See \ref send_sb.
259 * \param fmt The format string.
260 *
261 * \return The return value of the underlying call to \ref send_sb.
262 */
263 __printf_3_4 int send_sb_va(struct stream_cipher_context *scc, int band,
264 const char *fmt, ...)
265 {
266 va_list ap;
267 char *msg;
268 int ret;
269
270 va_start(ap, fmt);
271 ret = xvasprintf(&msg, fmt, ap);
272 va_end(ap);
273 return send_sb(scc, msg, ret, band, false);
274 }
275
276 /**
277 * Send an error message to a client.
278 *
279 * \param cc Client info.
280 * \param err The (positive) error code.
281 *
282 * \return The return value of the underlying call to send_sb_va().
283 */
284 int send_strerror(struct command_context *cc, int err)
285 {
286 return send_sb_va(&cc->scc, SBD_ERROR_LOG, "%s\n", para_strerror(err));
287 }
288
289 /**
290 * Send a sideband packet through a blocking file descriptor.
291 *
292 * \param scc fd and crypto keys.
293 * \param expected_band The expected band designator.
294 * \param max_size Passed to \ref sb_new_recv().
295 * \param result Body of the sideband packet is returned here.
296 *
297 * If \a expected_band is not \p SBD_ANY, the band designator of the received
298 * sideband packet is compared to \a expected_band and a mismatch is considered
299 * an error.
300 *
301 * \return Standard.
302 */
303 int recv_sb(struct stream_cipher_context *scc,
304 enum sb_designator expected_band,
305 size_t max_size, struct iovec *result)
306 {
307 int ret;
308 struct sb_context *sbc;
309 struct iovec iov;
310 struct sb_buffer sbb;
311 sb_transformation trafo;
312
313 trafo = expected_band != SBD_ANY && expected_band < SBD_PROCEED?
314 NULL : sc_trafo;
315 sbc = sb_new_recv(max_size, trafo, scc->recv);
316 for (;;) {
317 sb_get_recv_buffer(sbc, &iov);
318 ret = recv_bin_buffer(scc->fd, iov.iov_base, iov.iov_len);
319 if (ret == 0)
320 ret = -E_EOF;
321 if (ret < 0)
322 goto fail;
323 ret = sb_received(sbc, ret, &sbb);
324 if (ret < 0)
325 goto fail;
326 if (ret > 0)
327 break;
328 }
329 ret = -E_BAD_BAND;
330 if (expected_band != SBD_ANY && sbb.band != expected_band)
331 goto fail;
332 *result = sbb.iov;
333 return 1;
334 fail:
335 sb_free(sbc);
336 return ret;
337 }
338
339 static int com_sender(struct command_context *cc)
340 {
341 int i, ret = 0;
342 char *msg = NULL;
343 struct sender_command_data scd;
344
345 if (cc->argc < 2) {
346 for (i = 0; senders[i].name; i++) {
347 char *tmp;
348 ret = xasprintf(&tmp, "%s%s\n", msg? msg : "",
349 senders[i].name);
350 free(msg);
351 msg = tmp;
352 }
353 return send_sb(&cc->scc, msg, ret, SBD_OUTPUT, false);
354 }
355 ret = check_sender_args(cc->argc, cc->argv, &scd);
356 if (ret < 0) {
357 if (scd.sender_num < 0)
358 return ret;
359 if (strcmp(cc->argv[2], "status") == 0)
360 msg = senders[scd.sender_num].status();
361 else
362 msg = senders[scd.sender_num].help();
363 return send_sb(&cc->scc, msg, strlen(msg), SBD_OUTPUT, false);
364 }
365
366 switch (scd.cmd_num) {
367 case SENDER_ADD:
368 case SENDER_DELETE:
369 assert(senders[scd.sender_num].resolve_target);
370 ret = senders[scd.sender_num].resolve_target(cc->argv[3], &scd);
371 if (ret < 0)
372 return ret;
373 }
374
375 for (i = 0; i < 10; i++) {
376 mutex_lock(mmd_mutex);
377 if (mmd->sender_cmd_data.cmd_num >= 0) {
378 /* another sender command is active, retry in 100ms */
379 struct timespec ts = {.tv_nsec = 100 * 1000 * 1000};
380 mutex_unlock(mmd_mutex);
381 nanosleep(&ts, NULL);
382 continue;
383 }
384 mmd->sender_cmd_data = scd;
385 mutex_unlock(mmd_mutex);
386 break;
387 }
388 return (i < 10)? 1 : -E_LOCK;
389 }
390
391 /* server info */
392 static int com_si(struct command_context *cc)
393 {
394 int ret;
395 char *msg, *ut;
396
397 if (cc->argc != 1)
398 return -E_COMMAND_SYNTAX;
399 mutex_lock(mmd_mutex);
400 ut = daemon_get_uptime_str(now);
401 ret = xasprintf(&msg,
402 "up: %s\nplayed: %u\n"
403 "server_pid: %d\n"
404 "afs_pid: %d\n"
405 "connections (active/accepted/total): %u/%u/%u\n"
406 "current loglevel: %s\n"
407 "supported audio formats: %s\n",
408 ut, mmd->num_played,
409 (int)getppid(),
410 (int)mmd->afs_pid,
411 mmd->active_connections,
412 mmd->num_commands,
413 mmd->num_connects,
414 conf.loglevel_arg,
415 AUDIO_FORMAT_HANDLERS
416 );
417 mutex_unlock(mmd_mutex);
418 free(ut);
419 return send_sb(&cc->scc, msg, ret, SBD_OUTPUT, false);
420 }
421
422 /* version */
423 static int com_version(struct command_context *cc)
424 {
425 char *msg;
426 size_t len;
427
428 if (cc->argc > 1 && strcmp(cc->argv[1], "-v") == 0)
429 len = xasprintf(&msg, "%s", version_text("server"));
430 else
431 len = xasprintf(&msg, "%s\n", version_single_line("server"));
432 return send_sb(&cc->scc, msg, len, SBD_OUTPUT, false);
433 }
434
435 /** These status items are cleared if no audio file is currently open. */
436 #define EMPTY_STATUS_ITEMS \
437 ITEM(PATH) \
438 ITEM(DIRECTORY) \
439 ITEM(BASENAME) \
440 ITEM(SCORE) \
441 ITEM(ATTRIBUTES_BITMAP) \
442 ITEM(ATTRIBUTES_TXT) \
443 ITEM(HASH) \
444 ITEM(IMAGE_ID) \
445 ITEM(IMAGE_NAME) \
446 ITEM(LYRICS_ID) \
447 ITEM(LYRICS_NAME) \
448 ITEM(BITRATE) \
449 ITEM(FORMAT) \
450 ITEM(FREQUENCY) \
451 ITEM(CHANNELS) \
452 ITEM(DURATION) \
453 ITEM(SECONDS_TOTAL) \
454 ITEM(NUM_PLAYED) \
455 ITEM(LAST_PLAYED) \
456 ITEM(TECHINFO) \
457 ITEM(ARTIST) \
458 ITEM(TITLE) \
459 ITEM(YEAR) \
460 ITEM(ALBUM) \
461 ITEM(COMMENT) \
462 ITEM(MTIME) \
463 ITEM(FILE_SIZE) \
464 ITEM(CHUNK_TIME) \
465 ITEM(NUM_CHUNKS) \
466 ITEM(AMPLIFICATION) \
467
468 /**
469 * Write a list of audio-file related status items with empty values.
470 *
471 * This is used by vss when currently no audio file is open.
472 */
473 static unsigned empty_status_items(int parser_friendly, char **result)
474 {
475 char *esi;
476 unsigned len;
477
478 if (parser_friendly)
479 len = xasprintf(&esi,
480 #define ITEM(x) "0004 %02x:\n"
481 EMPTY_STATUS_ITEMS
482 #undef ITEM
483 #define ITEM(x) , SI_ ## x
484 EMPTY_STATUS_ITEMS
485 #undef ITEM
486 );
487 else
488 len = xasprintf(&esi,
489 #define ITEM(x) "%s:\n"
490 EMPTY_STATUS_ITEMS
491 #undef ITEM
492 #define ITEM(x) ,status_item_list[SI_ ## x]
493 EMPTY_STATUS_ITEMS
494 #undef ITEM
495 );
496 *result = esi;
497 return len;
498 }
499 #undef EMPTY_STATUS_ITEMS
500
501 /* stat */
502 static int com_stat(struct command_context *cc)
503 {
504 int i, ret;
505 struct misc_meta_data tmp, *nmmd = &tmp;
506 char *s;
507 int32_t num = 0;
508 int parser_friendly = 0;
509
510 para_sigaction(SIGUSR1, dummy);
511
512 for (i = 1; i < cc->argc; i++) {
513 const char *arg = cc->argv[i];
514 if (arg[0] != '-')
515 break;
516 if (!strcmp(arg, "--")) {
517 i++;
518 break;
519 }
520 if (!strncmp(arg, "-n=", 3)) {
521 ret = para_atoi32(arg + 3, &num);
522 if (ret < 0)
523 return ret;
524 continue;
525 }
526 if (!strcmp(arg, "-p")) {
527 parser_friendly = 1;
528 continue;
529 }
530 return -E_COMMAND_SYNTAX;
531 }
532 if (i != cc->argc)
533 return -E_COMMAND_SYNTAX;
534 for (;;) {
535 mmd_dup(nmmd);
536 ret = get_status(nmmd, parser_friendly, &s);
537 ret = send_sb(&cc->scc, s, ret, SBD_OUTPUT, false);
538 if (ret < 0)
539 goto out;
540 if (nmmd->vss_status_flags & VSS_NEXT) {
541 char *esi;
542 ret = empty_status_items(parser_friendly, &esi);
543 ret = send_sb(&cc->scc, esi, ret, SBD_OUTPUT, false);
544 if (ret < 0)
545 goto out;
546 } else
547 send_afs_status(cc, parser_friendly);
548 ret = 1;
549 if (num > 0 && !--num)
550 goto out;
551 sleep(50);
552 ret = -E_SERVER_CRASH;
553 if (getppid() == 1)
554 goto out;
555 }
556 out:
557 return ret;
558 }
559
560 static int send_list_of_commands(struct command_context *cc, struct server_command *cmd,
561 const char *handler)
562 {
563 char *msg = NULL;
564
565 for (; cmd->name; cmd++) {
566 char *tmp, *perms = cmd_perms_itohuman(cmd->perms);
567 tmp = make_message("%s\t%s\t%s\t%s\n", cmd->name, handler,
568 perms, cmd->description);
569 free(perms);
570 msg = para_strcat(msg, tmp);
571 free(tmp);
572 }
573 assert(msg);
574 return send_sb(&cc->scc, msg, strlen(msg), SBD_OUTPUT, false);
575 }
576
577 /* returns string that must be freed by the caller */
578 static struct server_command *get_cmd_ptr(const char *name, char **handler)
579 {
580 struct server_command *cmd;
581
582 for (cmd = server_cmds; cmd->name; cmd++)
583 if (!strcmp(cmd->name, name)) {
584 if (handler)
585 *handler = para_strdup("server"); /* server commands */
586 return cmd;
587 }
588 /* not found, look for commands supported by afs */
589 for (cmd = afs_cmds; cmd->name; cmd++)
590 if (!strcmp(cmd->name, name)) {
591 if (handler)
592 *handler = para_strdup("afs");
593 return cmd;
594 }
595 return NULL;
596 }
597
598 /* help */
599 static int com_help(struct command_context *cc)
600 {
601 struct server_command *cmd;
602 char *perms, *handler, *buf;
603 int ret;
604
605 if (cc->argc < 2) {
606 /* no argument given, print list of commands */
607 if ((ret = send_list_of_commands(cc, server_cmds, "server")) < 0)
608 return ret;
609 return send_list_of_commands(cc, afs_cmds, "afs");
610 }
611 /* argument given for help */
612 cmd = get_cmd_ptr(cc->argv[1], &handler);
613 if (!cmd)
614 return -E_BAD_CMD;
615 perms = cmd_perms_itohuman(cmd->perms);
616 ret = xasprintf(&buf, "%s - %s\n\n"
617 "handler: %s\n"
618 "permissions: %s\n"
619 "usage: %s\n\n"
620 "%s\n",
621 cc->argv[1],
622 cmd->description,
623 handler,
624 perms,
625 cmd->usage,
626 cmd->help
627 );
628 free(perms);
629 free(handler);
630 return send_sb(&cc->scc, buf, ret, SBD_OUTPUT, false);
631 }
632
633 /* hup */
634 static int com_hup(struct command_context *cc)
635 {
636 if (cc->argc != 1)
637 return -E_COMMAND_SYNTAX;
638 kill(getppid(), SIGHUP);
639 return 1;
640 }
641
642 /* term */
643 static int com_term(struct command_context *cc)
644 {
645 if (cc->argc != 1)
646 return -E_COMMAND_SYNTAX;
647 kill(getppid(), SIGTERM);
648 return 1;
649 }
650
651 static int com_play(struct command_context *cc)
652 {
653 if (cc->argc != 1)
654 return -E_COMMAND_SYNTAX;
655 mutex_lock(mmd_mutex);
656 mmd->new_vss_status_flags |= VSS_PLAYING;
657 mmd->new_vss_status_flags &= ~VSS_NOMORE;
658 mutex_unlock(mmd_mutex);
659 return 1;
660 }
661
662 /* stop */
663 static int com_stop(struct command_context *cc)
664 {
665 if (cc->argc != 1)
666 return -E_COMMAND_SYNTAX;
667 mutex_lock(mmd_mutex);
668 mmd->new_vss_status_flags &= ~VSS_PLAYING;
669 mmd->new_vss_status_flags &= ~VSS_REPOS;
670 mmd->new_vss_status_flags |= VSS_NEXT;
671 mutex_unlock(mmd_mutex);
672 return 1;
673 }
674
675 /* pause */
676 static int com_pause(struct command_context *cc)
677 {
678 if (cc->argc != 1)
679 return -E_COMMAND_SYNTAX;
680 mutex_lock(mmd_mutex);
681 if (!vss_paused() && !vss_stopped()) {
682 mmd->events++;
683 mmd->new_vss_status_flags &= ~VSS_PLAYING;
684 mmd->new_vss_status_flags &= ~VSS_NEXT;
685 }
686 mutex_unlock(mmd_mutex);
687 return 1;
688 }
689
690 /* next */
691 static int com_next(struct command_context *cc)
692 {
693 if (cc->argc != 1)
694 return -E_COMMAND_SYNTAX;
695 mutex_lock(mmd_mutex);
696 mmd->events++;
697 mmd->new_vss_status_flags |= VSS_NEXT;
698 mutex_unlock(mmd_mutex);
699 return 1;
700 }
701
702 /* nomore */
703 static int com_nomore(struct command_context *cc)
704 {
705 if (cc->argc != 1)
706 return -E_COMMAND_SYNTAX;
707 mutex_lock(mmd_mutex);
708 if (vss_playing() || vss_paused())
709 mmd->new_vss_status_flags |= VSS_NOMORE;
710 mutex_unlock(mmd_mutex);
711 return 1;
712 }
713
714 /* ff */
715 static int com_ff(struct command_context *cc)
716 {
717 long promille;
718 int ret, backwards = 0;
719 unsigned i;
720 char c;
721
722 if (cc->argc != 2)
723 return -E_COMMAND_SYNTAX;
724 if (!(ret = sscanf(cc->argv[1], "%u%c", &i, &c)))
725 return -E_COMMAND_SYNTAX;
726 if (ret > 1 && c == '-')
727 backwards = 1; /* jmp backwards */
728 mutex_lock(mmd_mutex);
729 ret = -E_NO_AUDIO_FILE;
730 if (!mmd->afd.afhi.chunks_total || !mmd->afd.afhi.seconds_total)
731 goto out;
732 promille = (1000 * mmd->current_chunk) / mmd->afd.afhi.chunks_total;
733 if (backwards)
734 promille -= 1000 * i / mmd->afd.afhi.seconds_total;
735 else
736 promille += 1000 * i / mmd->afd.afhi.seconds_total;
737 if (promille < 0)
738 promille = 0;
739 if (promille > 1000) {
740 mmd->new_vss_status_flags |= VSS_NEXT;
741 goto out;
742 }
743 mmd->repos_request = (mmd->afd.afhi.chunks_total * promille) / 1000;
744 mmd->new_vss_status_flags |= VSS_REPOS;
745 mmd->new_vss_status_flags &= ~VSS_NEXT;
746 mmd->events++;
747 ret = 1;
748 out:
749 mutex_unlock(mmd_mutex);
750 return ret;
751 }
752
753 /* jmp */
754 static int com_jmp(struct command_context *cc)
755 {
756 long unsigned int i;
757 int ret;
758
759 if (cc->argc != 2)
760 return -E_COMMAND_SYNTAX;
761 if (sscanf(cc->argv[1], "%lu", &i) <= 0)
762 return -E_COMMAND_SYNTAX;
763 mutex_lock(mmd_mutex);
764 ret = -E_NO_AUDIO_FILE;
765 if (!mmd->afd.afhi.chunks_total)
766 goto out;
767 if (i > 100)
768 i = 100;
769 PARA_INFO_LOG("jumping to %lu%%\n", i);
770 mmd->repos_request = (mmd->afd.afhi.chunks_total * i + 50) / 100;
771 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
772 mmd->chunks_sent, mmd->offset);
773 mmd->new_vss_status_flags |= VSS_REPOS;
774 mmd->new_vss_status_flags &= ~VSS_NEXT;
775 ret = 1;
776 mmd->events++;
777 out:
778 mutex_unlock(mmd_mutex);
779 return ret;
780 }
781
782 static int com_tasks(struct command_context *cc)
783 {
784 char *tl = server_get_tasks();
785 int ret = 1;
786
787 if (tl)
788 ret = send_sb(&cc->scc, tl, strlen(tl), SBD_OUTPUT, false);
789 return ret;
790 }
791
792 /*
793 * check if perms are sufficient to exec a command having perms cmd_perms.
794 * Returns 0 if perms are sufficient, -E_PERM otherwise.
795 */
796 static int check_perms(unsigned int perms, const struct server_command *cmd_ptr)
797 {
798 PARA_DEBUG_LOG("checking permissions\n");
799 return (cmd_ptr->perms & perms) < cmd_ptr->perms ? -E_PERM : 0;
800 }
801
802 static void reset_signals(void)
803 {
804 para_sigaction(SIGCHLD, SIG_IGN);
805 para_sigaction(SIGINT, SIG_DFL);
806 para_sigaction(SIGTERM, SIG_DFL);
807 para_sigaction(SIGHUP, SIG_DFL);
808 }
809
810 struct connection_features {
811 bool sideband_requested;
812 bool aes_ctr128_requested;
813 };
814
815 static int parse_auth_request(char *buf, int len, struct user **u,
816 struct connection_features *cf)
817 {
818 int ret;
819 char *p, *username, **features = NULL;
820 size_t auth_rq_len = strlen(AUTH_REQUEST_MSG);
821
822 *u = NULL;
823 memset(cf, 0, sizeof(*cf));
824 if (len < auth_rq_len + 2)
825 return -E_AUTH_REQUEST;
826 if (strncmp(buf, AUTH_REQUEST_MSG, auth_rq_len) != 0)
827 return -E_AUTH_REQUEST;
828 username = buf + auth_rq_len;
829 p = strchr(username, ' ');
830 if (p) {
831 int i;
832 if (p == username)
833 return -E_AUTH_REQUEST;
834 *p = '\0';
835 p++;
836 create_argv(p, ",", &features);
837 for (i = 0; features[i]; i++) {
838 if (strcmp(features[i], "sideband") == 0)
839 cf->sideband_requested = true;
840 else if (strcmp(features[i], "aes_ctr128") == 0)
841 cf->aes_ctr128_requested = true;
842 else {
843 ret = -E_BAD_FEATURE;
844 goto out;
845 }
846 }
847 }
848 PARA_DEBUG_LOG("received auth request for user %s\n", username);
849 *u = lookup_user(username);
850 ret = 1;
851 out:
852 free_argv(features);
853 return ret;
854 }
855
856 #define HANDSHAKE_BUFSIZE 4096
857
858 static int run_command(struct command_context *cc, struct iovec *iov,
859 const char *peername)
860 {
861 int ret, i;
862 char *p, *end;
863 struct server_command *cmd;
864
865 if (iov->iov_base == NULL || iov->iov_len == 0)
866 return -E_BAD_CMD;
867 p = iov->iov_base;
868 p[iov->iov_len - 1] = '\0'; /* just to be sure */
869 cmd = get_cmd_ptr(p, NULL);
870 if (!cmd)
871 return -E_BAD_CMD;
872 ret = check_perms(cc->u->perms, cmd);
873 if (ret < 0)
874 return ret;
875 end = iov->iov_base + iov->iov_len;
876 for (i = 0; p < end; i++)
877 p += strlen(p) + 1;
878 cc->argc = i;
879 cc->argv = para_malloc((cc->argc + 1) * sizeof(char *));
880 for (i = 0, p = iov->iov_base; p < end; i++) {
881 cc->argv[i] = para_strdup(p);
882 p += strlen(p) + 1;
883 }
884 cc->argv[cc->argc] = NULL;
885 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd->name,
886 cc->u->name, peername);
887 ret = cmd->handler(cc);
888 free_argv(cc->argv);
889 mutex_lock(mmd_mutex);
890 mmd->num_commands++;
891 if (ret >= 0 && (cmd->perms & AFS_WRITE))
892 mmd->events++;
893 mutex_unlock(mmd_mutex);
894 return ret;
895 }
896
897 /**
898 * Perform user authentication and execute a command.
899 *
900 * \param fd The file descriptor to send output to.
901 * \param peername Identifies the connecting peer.
902 *
903 * Whenever para_server accepts an incoming tcp connection on the port it
904 * listens on, it forks and the resulting child calls this function.
905 *
906 * An RSA-based challenge/response is used to authenticate the peer. It that
907 * authentication succeeds, a random session key is generated and sent back to
908 * the peer, encrypted with its RSA public key. From this point on, all
909 * transfers are crypted with this session key.
910 *
911 * Next it is checked if the peer supplied a valid server command or a command
912 * for the audio file selector. If yes, and if the user has sufficient
913 * permissions to execute that command, the function calls the corresponding
914 * command handler which does argument checking and further processing.
915 *
916 * In order to cope with a DOS attacks, a timeout is set up which terminates
917 * the function if the connection was not authenticated when the timeout
918 * expires.
919 *
920 * \sa alarm(2), crypt.c, crypt.h
921 */
922 __noreturn void handle_connect(int fd, const char *peername)
923 {
924 int ret;
925 unsigned char rand_buf[CHALLENGE_SIZE + 2 * SESSION_KEY_LEN];
926 unsigned char challenge_hash[HASH_SIZE];
927 char *command = NULL, *buf = para_malloc(HANDSHAKE_BUFSIZE) /* must be on the heap */;
928 size_t numbytes;
929 struct command_context cc_struct = {.peer = peername}, *cc = &cc_struct;
930 struct iovec iov;
931 struct connection_features cf;
932
933 cc->scc.fd = fd;
934 reset_signals();
935 /* we need a blocking fd here as recv() might return EAGAIN otherwise. */
936 ret = mark_fd_blocking(fd);
937 if (ret < 0)
938 goto net_err;
939 /* send Welcome message */
940 ret = write_va_buffer(fd, "This is para_server, version "
941 PACKAGE_VERSION ".\n"
942 "Features: sideband,aes_ctr128\n"
943 );
944 if (ret < 0)
945 goto net_err;
946 /* recv auth request line */
947 ret = recv_buffer(fd, buf, HANDSHAKE_BUFSIZE);
948 if (ret < 0)
949 goto net_err;
950 ret = parse_auth_request(buf, ret, &cc->u, &cf);
951 if (ret < 0)
952 goto net_err;
953 if (!cf.sideband_requested) { /* sideband is mandatory */
954 PARA_ERROR_LOG("client did not request sideband\n");
955 ret = -E_BAD_FEATURE;
956 goto net_err;
957 }
958 if (cc->u) {
959 get_random_bytes_or_die(rand_buf, sizeof(rand_buf));
960 ret = pub_encrypt(cc->u->pubkey, rand_buf, sizeof(rand_buf),
961 (unsigned char *)buf);
962 if (ret < 0)
963 goto net_err;
964 numbytes = ret;
965 } else {
966 /*
967 * We don't want to reveal our user names, so we send a
968 * challenge to the client even if the user does not exist, and
969 * fail the authentication later.
970 */
971 numbytes = 256;
972 get_random_bytes_or_die((unsigned char *)buf, numbytes);
973 }
974 PARA_DEBUG_LOG("sending %u byte challenge + session key (%zu bytes)\n",
975 CHALLENGE_SIZE, numbytes);
976 ret = send_sb(&cc->scc, buf, numbytes, SBD_CHALLENGE, false);
977 buf = NULL;
978 if (ret < 0)
979 goto net_err;
980 ret = recv_sb(&cc->scc, SBD_CHALLENGE_RESPONSE,
981 HANDSHAKE_BUFSIZE, &iov);
982 if (ret < 0)
983 goto net_err;
984 buf = iov.iov_base;
985 numbytes = iov.iov_len;
986 PARA_DEBUG_LOG("received %zu bytes challenge response\n", numbytes);
987 ret = -E_BAD_USER;
988 if (!cc->u)
989 goto net_err;
990 /*
991 * The correct response is the hash of the first CHALLENGE_SIZE bytes
992 * of the random data.
993 */
994 ret = -E_BAD_AUTH;
995 if (numbytes != HASH_SIZE)
996 goto net_err;
997 hash_function((char *)rand_buf, CHALLENGE_SIZE, challenge_hash);
998 if (memcmp(challenge_hash, buf, HASH_SIZE))
999 goto net_err;
1000 /* auth successful */
1001 alarm(0);
1002 PARA_INFO_LOG("good auth for %s\n", cc->u->name);
1003 /* init stream cipher keys with the second part of the random buffer */
1004 cc->scc.recv = sc_new(rand_buf + CHALLENGE_SIZE, SESSION_KEY_LEN,
1005 cf.aes_ctr128_requested);
1006 cc->scc.send = sc_new(rand_buf + CHALLENGE_SIZE + SESSION_KEY_LEN,
1007 SESSION_KEY_LEN, cf.aes_ctr128_requested);
1008 ret = send_sb(&cc->scc, NULL, 0, SBD_PROCEED, false);
1009 if (ret < 0)
1010 goto net_err;
1011 ret = recv_sb(&cc->scc, SBD_COMMAND, MAX_COMMAND_LEN, &iov);
1012 if (ret < 0)
1013 goto net_err;
1014 ret = run_command(cc, &iov, peername);
1015 free(iov.iov_base);
1016 if (ret < 0)
1017 goto err_out;
1018 if (ret >= 0)
1019 goto out;
1020 err_out:
1021 if (send_strerror(cc, -ret) >= 0)
1022 send_sb(&cc->scc, NULL, 0, SBD_EXIT__FAILURE, true);
1023 net_err:
1024 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
1025 out:
1026 free(buf);
1027 free(command);
1028 mutex_lock(mmd_mutex);
1029 mmd->active_connections--;
1030 mutex_unlock(mmd_mutex);
1031 if (ret >= 0) {
1032 ret = send_sb(&cc->scc, NULL, 0, SBD_EXIT__SUCCESS, true);
1033 if (ret < 0)
1034 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
1035 }
1036 sc_free(cc->scc.recv);
1037 sc_free(cc->scc.send);
1038 exit(ret < 0? EXIT_FAILURE : EXIT_SUCCESS);
1039 }